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By Albert W. Deurbrouck

Twelve samples from six Barbour County coal beds were analyzed for this report. The samples collected were generally high sulfur content coals, frequently exceeding 3 percent in the raw-coal sample. Many of them could not be upgraded to acceptable metallurgical standards even by rigorous preparation procedures. The production of coal in the county in 1963 amounted to almost 3 million tons of which 44 percent was mechanically cleaned.

Jan 1, 1965

By Robert L. de Beauchamp

The Bureau of Mines reviewed aluminum chloride technology to determine the problems associated with its preparation from minerals, and to ascertain the best areas for research to solve these problems. Commercial AlC13 production processes are described and the ?state of the art? for the preparation of AlC13 from aluminous materials is evaluated. Areas for further research are indicated.

Jan 1, 1969

By R. L. Grayson, T. Simonyi, R. A. Andrel

"The purpose or this paper is to disclose analytical, statistical, and observational results relating to mineralogy and trace elements in respirable dust samples collected from two different mines in West Virginia. Samples were taken from longwall panels, and the panels operated in different coal seams, one located in the northern part or the state and the other in the southern region. Mining conditions and equipment arrangements on the panels will be described along with dust control techniques used. Results from sample analyses are summarized with emphasis on relationships between mineralogy, trace elements and mineral particle size to worker locations. Correlations are made between micro x-ray diffraction and energy dispersive x-ray analyses for sample mineralogy.IntroductionThrough the work of many researchers worldwide, the health of coal miners in modern societies is now protected from harmful exposure to respirable coal mine dust. A vast amount of research culminated in the exposure-response model of Jacobsen, et al, (l) which has been used to establish the 2 mg/m3 exposure limit in the United States. According to the model exposure to respirable dust for 35 years at this level or less could prevent the occurrence of a clinically significant case of coal workers' pneumoconiosis (CWP) in a miner. The exposure limit, of course, must be adjusted whenever greather than five percent free silica exists in the respirable dust.The Jacobsen model was built around a mean mass concentration exposure, which generally showed the highest correlation with both incidence and progression of CWP. As Morgan, et al noted, however, the quantity of respirable dust inhaled is not the only significant factor. 2) They noted that although mass of respirable dust correlates highe.st with the incidence of CWP, it is not a causal factor. Admittedly, the insidious processes causing the disease occur at the lund cell-dust particle level."

Mar 1, 1989

By W. H. Ryback

When a fire or explosion occurs in an underground coal mine, the atmosphere guickly becomes irrespirable. Highly irritant smoke and toxic levels of carbon monoxide and dioxide are produced, and consumption of oxygen by the fire or blast can reduce its concentration below that needed to support life. Work parties entering such a hazardous atmosphere for rescue or recovery operations are required to use, as their primary respiratory protection, a fully self-contained breathing apparatus of at least two hours duration. Apparatus used in this role has primarily been of the closed circuit rebreather type, using pressurized oxygen storage and chemical removal of expired carbon dioxide. Typically, commercial self-contained breathing devices for mine rescue have been heavy, bulky, and uncomfortable to use. The McCaa apparatus, long the industry standard, represented the best art available when it was First designed in 1926. It weighs 41 Ibs., protrudes about six inches above shoulder height, and provides breathing gas at temperatures up to 120° F. More recent designs, such as the Drager BG174A and Scott Rescue-Pak, using modern light weight materials and fabrication techniques have improved on all parameters of the McCaa to some extent. It was the intent of the Bureau of Mines, acting under the authority of the Coal Mine Health and Safety Act of 1969, to fund the development of a new self-contained breathing apparatus which would incorporate the best available technology and serve as a benchmark for future commercial designs, as the Bureau-sponsored McCaa had 45 years previously.

Jan 1, 1974

By J. Douglas Causey

In 1985, at the request of the Bureau of Land Management, the U.S. Bureau of Mines studied a portion of the 110,000 acre Massacre Rim Wilderness Study Area (CA-020-1013). The area studied, containing 23,260 acres, is located in northwest Washoe County, Nevada, about 25 miles west of Vya adjoining the Charles Sheldon National Wildlife Refuge. Basalt caps older tuffaceous sedimentary rocks in an area that contains no claims or prospects. No mineral resources were identified during this investigation.

Jan 1, 1987

By H. D. BAILEY, John W. Cole

This paper is one of a series on mining methods and costs published by the Bureau of Mines .. Because of the role, played by the Federal Government in the discovery of the ore body, a description of the exploratory operations of the Bureau of Mines, is included ...

Apr 1, 1948

By D. A. Baker

This report describes the elemental characterization of chromite and related materials at the Bureau of Mines, Albany Research Center. Analytical methods for determining the major constituents, representing extensive experience, refinement, and development, are described and fully annotated. This presentation should allow other laboratories to use these methods and obtain comparable results with a minimum of time needed for familiarization with individual methods.

Jan 1, 1990

By Gary A. Kingston

Domestic nickel resources are costed to develop a contingency supply curve of U.S. nickel availability at various costs. It is estimated that 4.3 billion pounds of nickel is potentially recoverable from 698 million tons of ore at prices ranging up to $6.36 per pound of nickel. Over 95 percent of the total is estimated to be available at a price of less than $4.00 per pound.

Jan 1, 1970

By Joseph H. White

In its investigations looking to the improvement of health condi- tions and the increase of efficiency in the mining industry, the Bureau of Mines, in cooperation with the Bureau of Public Health, is studying sanitary conditions in and about mines with the intent of pointing out how those conditions that are a menace to the health of the miner may be most efficiently removed or remedied. An out- line of sanitary betterment work at mining villages in the Birming- ham district of Alabama has already been published by the bureau," and in this bulletin are presented suggestions on the planning of mining towns and the construction of miners' houses. The bulletin does not pretend to be a treatise on the so-called "housing problem," and mentions sociologic issues only incidentally. It is assumed that the influence of proper shelter on health is understood and that not a lack of appreciation so much as a lack of knowledge of the best remedies is responsible for many of the undesirable conditions that exist at mining towns. The purpose of this bulletin is to supply facts on the building of well-lighted, well- ventilated, warm, attractive, and economical houses for miners, these houses being assumed to be units of an industrial village or town the building and management of which are under the control of a corporation, so that special conditions hold which do not apply to houses built and owned by individual miners. From this it is not to be inferred that the company-controlled town is the best system or the only one in vogue. The discussion of this side of the subject in all its phases is too involved to be included in this paper. One element in favor of the company-controlled town is its possible immediate responsiveness. Hence this assumption. Also the assumption is made that a-new isolated town is being built, and hence the selection of the site, the arrangement of the streets, and the situation of the houses are discussed before the house itself is treated, for one of the most important factors in obtaining an economical sanitary house is a well-selected town site. Many of the suggestions, however, may be applied in improving conditions in existing towns, in building new houses in old towns, or in repairing old houses. Emphasis must be laid on the fact that as a rule a mining village has a shorter life than a manufacturing town. Economy is emphasized frequently because the discussion is predi- cated upon the assumption that the miner himself is to pay for all that he gets. House rent will doubtless be expected to bring in a reasonable return on all money invested in streets, sidewalks, water supply, sewer system, and houses; in other words, the town is to be run on a business and not on a paternal or charitable basis. "Fair and reasonable" precludes, of course, the idea of excessive returns. Some companies do not consider it good policy to realize as high a rate of interest as an independent realty company would be war- ranted in realizing. Under some circumstances part of the town improvements might be charged as "expense of the industry," that is, to the consumer. The isolation of a mining town introduces a unique responsibility. As the miners are practically obliged to rent the company houses, the officials of the company ought to scrutinize all expenditures in- volved so that house rent may be reduced to a minimum. In a way the town builders are placed in the position of trustees. They deter- mine, within certain limits, what proportion of a man's wages shall be spent on house rent. This consideration should restrain fanciful and unnecessarily expensive building; the other extreme should like- wise be avoided. True economy should be distinguished from cheap- ness. Ugly, insanitary, uncomfortable shacks should not be built even if, because of their cheapness, there is a demand for them from tenants. The obligation of the industry to society as a whole as well us to the tenant ought to forbid this. A cheerful, strong, healthy, virile race will not rise out of the filth and squalor of cheap hovels. An insanitary environment often does its damage slowly and silently; vitiated air does not, like mine gas, announce its deadly work by an explosion. As Talbot⚫ says: Health depends in part on freedom from infection. The probability of obtain- ing that freedom will be greatly increased by maintaining the body at a high state of vigor, or "vitality," as it is popularly called. This implies the promo- tion of all agencies which have to do with the physical well-being as well as with the control of sources of infection. Many men realize that in building houses for their workmen they are invested with a peculiar responsibility that must be wielded wisely, and in large developments they call into consultation the land- scape architect, the sanitary engineer, and the building architect, as well as the mining engineer.

Jan 1, 1914

By Robert L. Lagace

[Suuple Iheorctrccil models are I'M lllolalcd to cltaraclerl/c medium frequency (MF) radio vase pi opaiation in undcrgiounli room arid pillar coal mines fur the purpose of predleiln the most lavolable operating fIegtucncics,md nr,ixunum communic;IIIoil ranges for pottahIe rldu)s with I top antennas. I or conductul IrCC areas, at hree layer propaeaIion IltodcI wit II a Iiallsmissloil IIIIi- lhlllllIIal'u11 lot the plupa!edti ii unlstallt Iris been dcvcloped ;md verified experimentally. 1 lie mode u1 propaCaUetl lakes Ills form of i parallel plane (0,t)) TIM lransnussu)nhne 1% PC of mode with the electric held vertical and the magnetic held hoti/cntal t itliin a planar coal scam in which the tunnels Can he ignored and which 1s hounded above and below hp richer conductivity rock. 1lie model lilt the data best river the 200 io 1000 kH/ frequency hand and exhibits a rc;;lon of optlnrul1l Pelffelntance, with respect Io maxnluiulg radio Communication range, between 300 and 100 klf/. Maximum cunununlcatrorl ranges are sliongls dependent oil the sigiial alleilliatroil sale, ant) Illelclulc on the electrical conductivltles of the coal seam and surrounding ruck. These ranges v;ny tutu about ,,5 Io 100 nleleis Ill a high Iuss scam such as the Ilelllit No. fl to about .100 to 400 meters in a low loss seam such as the Pittsburgh foil portable intrinsically safe radios. The ieslllls die haled on the comparison oftheorc' and experiment for eleven n n. ill sesen coal seams. V OT ate is dice: a conductor such as a power Cable, is present a model has been developed for the coupling of loop antennas to a low loss Coaxial TEM ti;u?smisslon line mode in which the cable acts as the inner conducl,lr and the rock above and below acts as the outer conductor. The electuc and md' nctic Itelds for till` (node are apprlixitllatcly transverse to the cahlC and fall oil expontially with distance in the transverse plane. The principle of reciprocity is used to simplify the analysis. More expelitnental data arc needed to help resolve discrepancies between the theory and the limited data available to date.]

Jan 1, 1980

By Robert C. Dyni

The Bureau of Mines in cooperation with the Solution Mining Research Institute conducted surface and subsurface investigations over five solution-mined salt cavities in the Hutchinson, KS, area. The purpose of these investigations was to determine the mechanisms that lead to the formation of sinkholes above collapsed solution cavities. Of the five salt-solution cavities investigated, four had collapsed and produced sinkholes prior to the time of the investigations; the fifth cavity was considered stable. Exploratory drilling and coring operations were conducted at all five sites; surface stability monitoring was conducted at three of them. The results of these studies indicate that excessive dissolution at the salt-shale contact of each collapsed cavity produced large, unsupported roof spans that ultimately exceeded the structural integrity of the overburden. The stable cavity was not exposed to excessive dissolution at the salt-shale contact; this limited the roof span and ensured a stable cavity. The data also show that surface settlement in the vicinity of the two surface-monitored sinkholes continued for approximately 7 years after the sinkholes formed, indicating that the rubble piles of the collapsed cavities were undergoing gradual consolidation.

Jan 1, 1986

By John E. Pahlman

The Bureau of Mines has conducted research on a dual leaching method that offers the potential for the economic recovery of the silver, as well as of the manganese, contained in some domestic manganiferous silver deposits. The method consists of an initial leach of manganese with aqueous sulfur dioxide (S02) followed first by a neutralization rinse, and then by a second leach with cyanide solution for the extraction of silver. Refractory silver in these ores was either (1) intimately associated with the manganese, (2) chemically resistant to cyanide leaching, or (3) rendered inaccessible to cyanide leach solution by the surrounding manganese mineralization. Less than 10 pct of the silver was extracted when minus 2.5-plus 1.3-cm ore pieces were leached directly with cyanide. However, extractions of 25 to 82 pct of the silver and 65 to 96 pet of the manganese were attained in laboratory column-leach tests using the dual leaching method on equivalent-sized ore pieces from seven domestic deposits.

Jan 1, 1987

By L. E. Schultze

Experiments were conducted by the U.S. Bureau of Mines to verify enhancements due to chloride and surfactant additions in the leaching system of chalcopyrite with ferric sulfate and sulfuric acid. A statistical experimental design was used and equipment was designed to eliminate contributions from changes in solution electrochemical potential during the course of the measurements. Results confirmed that chloride additions increased chalcopyrite leaching by as much as 94 pct over the electrochemical potential versus hydrogen electrode range of 630 to 750 mV at pH 1.7 and 50°C. Total iron concentration had no effect over the range of 1 to 5 g/L. The effect of surfactant addition was less well defined. While additions of LA 790 (a polyoxyethylene lauryl ether) resulted in increased copper leaching in several of the tests, the differences were too small to be statistically significant. No interaction effect could be verified.

Jan 1, 2010

By M. Orchin

THIS PAPER is concerned with two aspects of the behavior of coal: (1) Dispersion by solvents atmospheric pressure and high temperature and (2) the destruction and regeneration of the coking properties of coal. Several pure polycyclic compounds and a coal-tar fraction were found to extract 95 percent of the organic material of a bituminous coal. About 20 percent of the extract was soluble in benzene, and this fraction contained the ?coking principle? of the coal. From an extensive chemical spectroscopic, and x-ray study of the benzene-soluble material, some conclusions could be drawn concerning the composition and structure of this fraction of coal. A possible commercial application of the extraction technique is in the preparation of low-ash carbonaceous material for the manufacture of electrode carbon.

Jan 1, 1951

By Susan Brink

The U.S. Bureau of Mines is investigating the potential of in situ leach mining a variety of Cu, Mn, and Au-Ag ores. Geologic characterization of ore samples from laboratory leaching experiments is conducted both prior to and after leaching to assess the effects of leaching on the chemistry, mineralogy, and texture of the rocks. The identification and chemical compositions of ore, gangue, and reaction products are determined by a combination of techniques such as reflected and transmitted light microscopy, X-ray diffraction, electron diffraction, electron microprobe analysis, and backscattered electron imaging with scanning electron microscopy. The distribution of the desired metal in various mineral phases can be illustrated using elemental X-ray maps. The potential of reactive gangue minerals to rob Cu from leach solutions is investigated with the aid of transmission electron microscopy. Porosity and permeability are measured to determine how effectively the host rock can transmit leach solution. Textural relationships between ore, gangue, secondary reaction products, and fluid channelways are determined by petrographic examination and are documented by optical photomicrographs and secondary electron imaging. Representative sample selection is described, and several epoxy impregnation and sample mounting techniques are discussed.

Jan 1, 1991

By Jeffrey H. Welsh

This report presents a study on the use of computerized, continuous remote monitoring systems for fire and explosive atmosphere safety in underground coal mines. The effects of these systems on the safety level in mines are investigated, and the relationship between mine safety regulations and computerized, continuous, remote monitoring is analyzed.

Jan 1, 1982

By Allen D. Look

In the prevention of accidents in milling operations, the proper installation and guarding of electrical and mechanical equipment, safe clearances, good housekeeping, adequate fire protection, adequate ventilation, dust and fume control, and good illumination, as well as safe practices, are essential. In the new concentrator of the Magna Copper Co., Superior, Ariz., many safeguards were incorporated and safe practices instituted to minimize accident hazards. The purpose of this paper is to describe some of these features and practices.

Jan 1, 1951

By Ronald S. Conti

Historically, underground mine rescue teams have received training only in the course of actual emergencies, or in simulated mine environments, usually on the surface, with placards to identify objects and hazards. Also, while U.S. Federal Regulations require all underground miners to walk escapeways and conduct fire drills every 90 days, this does not fully prepare them for the conditions that may be encountered in real escape situations, such as smoke filled entries. This paper describes technology and realistic training simulations that have been identified for the general workforce and mine emergency responders. Of all the technology evaluated by underground personnel, laser lights and lifelines were most beneficial in leading personnel to safety and out of the mine in smoke-filled passageways. These technological advancements can improve the state of readiness for rescue personnel and increase the chances of survival for personnel escaping from underground emergencies.

By Verne E. Hooker

In situ stresses, based on isotropic and anisotropic relations, were evaluated using computer techniques from overcoring data obtained in dimension stone quarries along the Appalachian Piedmont, the Ozark Uplift, and the Ouachita Tectonic Belt. Stresses in the horizontal plane near the surface are compressive and range from 100 to 4,500 psi. The direction of maximum compressive stress seems to be alined with the general tectonic structure for most of the determinations. The ratio of the maximum to minimum elastic parameters in the horizontal plane ranges from 1.05 to 2.46 for these competent rocks. Isotropic versus anisotropic stress determinations show differences only as great as 25 percent in stress magnitude and 25° in orientation.

Jan 1, 1969

By Paul Hatmaker

This paper covers briefly the particular field of dolomite and magnesium limestone; certain uses of high-calcium limestone are mentioned only to show more clearly the limita¬ tions of the magnesian rocks. Such a comparison is helpful because magnesium carbonate is essential for some uses; for others it is immaterial; and for many its presence in an appreciable amount is objectionable. Magnesium carbonate, occurring as a rock resembling limestone or dolomite, is described in United States Bureau of Mines Information Circular 6437, Magnesite. Other com¬ pounds of magnesium are described in United States Bureau of Mines Information Circular 6406, Magnesium Compounds (Other Than Magnesite). Limestone, geologically, is a rock composed essentially of calcium carbonate; commercially, however, the term may include dolomite and magnesium limestone.

Sep 1, 1931